Radial outflow decomposition chamber



June 3, 1969 w. 0. WHITE I RADIAL OUTFLOW DECOMPOSITION CHAMBER Filed June 7, 1965 FIG. 2.

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United States Patent "ice 3,447,316 RADIAL OUTFLOW DECOMPOSITION CHAMBER William D. White, Pasadena, Calif., assignor to the United States of America as represented by the Secretary of the Navy Filed June 7, 1965, Ser. No. 462,152

Int. Cl. F02k 9/02, 7/08 Us. or. 60-39.46 4 Claims ABSTRACT OF THE DISCLOSURE The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to gas generator or rocket motors and more particularly to improvements in catalytic decomposition apparatus for use with the same.

It has been known practice to decompose a material, such as hydrogen peroxide, by passing it through a porous bed or chamber containing a catalyst, the products of decomposition being employed for operating a hot gas engine .or for producing thrust for a rocket propelled vehicle. Such decomposition chambers are usually formed of. axially stacked disc shaped screens within a cylindrical chamber, the liquid material being delivered to one end of the cylinder and the gaseous decomposition products exhausting from the other end.

Decomposition chambers of the type just referred to suffer the disadvantage of high pressure drops since the cross-sectional area available for flow is constant whereas the volume flow is continuously increasing due to the progressive decomposition of the material. While such chamber configuration could be designed with sufficient cross sectional area to provide a desired low pressure drop it would then be unnecessarily bulky and heavy and contain considerably more catalyst surface than necessary to decompose the material at a desired flow rate.

When a decomposition chamber of the type referred to is utilized to provide oxygen to oxidize a fuel in a bipropellant system, the fuel delivery conduit is sometimes arranged to pass through or adjacent the catalyst chamber and hence in heat transfer relation to the hot decomposition products. If the fuel is such that it forms solid residue when heated, clogging of the small fuel injection orifices may occur. Another disadvantage of such arrarigement of fuel conduit is that the flow properties of the fuel through the injection orifices is a function of-fuel temperature which coplicates flow control.

One of the objects of this invention is to provide a catalytic decomposition chamber in which successive downstream cross-sections increase in proportion to the increasing volume of the products of decomposition.

Another object is to provide such chamber with a minimum pressure drop with a minimum area of catalytic surface.

Another object is to provide a bi-propellant system in which fuel is delivered to an injection nozzle in heat trans- 3,447,316 Patented June 3, 1969 fer relation to a surrounding relatively cold decomposable liquid material.

A further object is to provide a novel arrangement of decomposition chamber, fuel delivery conduit and fuel injection nozzle.

Still further objects, advantages and salient features will become more apparent from the description to follow, the appended claims and the accompanying drawing, in which:

FIG. 1 is an end elevation of the subject of the invention;

FIG. 2 is a greatly enlarged section taken on line 22, FIG. 1;

FIG. 3 is a detail as viewed in the direction of arrow 3, FIG. 2; and

FIG. 4 is a like detail as viewed in the direction of arrow 4, FIG. 2.

Referring now to the drawing, and particularly to FIG. 2, an exemplary environment for the subject of the invention comprises a cylindrical plug member 10, closing one end of a motor tube 12, from which gas under pressure is delivered to a hot gas engine (not shown) or any suitable nozzle for producing thrust.

A spool-like member 14, having a hub 16, is secured to member 10 by threads 18, member 14 having a bore into which extends a fuel conduit 20, threadedly engaging member 10. An annular space 22 is provided around conduit 20 to which liquid hydrogen peroxide may be delivered through a conduit 24. A plurality of angularly spaced rows of apertures 26 extend through the hub for delivery of the hydrogen peroxide to the decomposition chamber to be subsequently described.

A disc-like member 28 is secured to member 18 by threads 30, fuel conduit 20 extending into a central bore in member 28. Suitable O-rings, as shown, prevent leakage across the various joints. Member 28 is provided with a conical nozzle 32, having angularly spaced ejection orifices 34, communicating with the fuel conduit. An annular outwardly flaring frusto-conical bafile 36, having angularly spaced apertures 38, surrounds nozzle 32.

As will be apparent, opposed surfaces of spool 14 and members 10, 28 form an annular space 40 surrounding hub 16. This space provides the chamber in which the decomposition occurs and which contains the catalyst screen to now be described.

Referring to FIGS. 3 and 4, two strips of silver plated screen 42, 44, one being straight cut and the other being bias cut, are disposed in facial juxtaposition and wrapped around the spool in an Archimedian spiral, filling the annular space. The purpose of the straight and bias arrangements of the screen mesh is to prevent the screen apertures of successive coils from being in alignment, thus providing a more tortuous and uniform radial outward flow of hydrogen peroxide and hence maximum contact with the silver catalyst. Any desired securing means, such as a perforated clamping band 46, may be employed to maintain the coils in their intended position. The screen, forming the catalyst substrate, may be of copper or iron and the silver catalyst is preferably plated upon it as a rough or mossy coating to provide maximum surface of the catalyst.

In operation, a fuel, such as a slurry of magnesium powder in a liquid hydrocarbon is delivered through conduit 20 and ejection orifices 34. Liquid hydrocarbon peroxide is simultaneously delivered through conduit 24 and spool apertures 26 to the decomposition chamber where it flows radially outwardly and decomposes. The products of decomposition then flow in the direction of arrow 48, a portion being delivered through apertures 38 for atomizing the fuel delivered through apertures 34 and another portion being delivered into the combustion chamber 50 where it reacts with the atomized fuel. If cooling of the products of combustion is desired, water or other coolant may be injected through orifices 52 communicating with an annular coolant supply manifold 54.

While a silver catalyst is satisfactory for use with up to about 90% hydrogen peroxide, higher concentrations may produce sufficiently high decomposition temperatures to melt the silver. For these higher concentrations other catalysts such as cobalt oxide may be employed. To effect more rapid initial decomposition during the heating period of the bed any of the foregoing catalysts may be coated with potassium permanganate or samarium nitrate which are washed away during the heating period. As previously referred to the screen serves as a substrate or support for the catalyst particles to maintain a porous bed. A substrate, however, is not essential in all cases since the catalyst may be in pellet form, filling the annular space and retained in same by a suitable surrounding screen in lieu of band 46. As will also now be apparent the decomposition bed may be utilized with any other catalytically decomposable liquid, such as hydrazine.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. Apparatus for decomposing a catalytically decomposable liquid into gaseous products of decomposition comprising:

a chamber having opposed spaced imperforate walls and a central opening extending therebetween, defining an annular space,

a porous substrate material having catalytic surfaces, filling said annular space and forming an annular decomposition bed,

means for delivering a catalytically decomposable liquid to said central opening for outward flow therefrom in all radial directions through the bed, the products of decomposition exhausting throughout the periphery of the bed,

a fuel conduit extending axially through said central opening and in heat transfer relation to surrounding decomposable liquid delivered to said central opena,

a fuel injection nozzle disposed adjacent one side of said bed and communicating with said conduit,

said nozzle having a plurality of angularly spaced injection orifices arranged to inject the fuel in outwardly directed streams from the surface of a cone,

an annular baflle surrounding said nozzle having a plurality of angularly spaced orifices arranged to deliver gaseous products of decomposition in inwardly directed streams along the surface of a cone and intersecting the streams of fuel, for atomizing same, and 5 an annular passage surrounding said batiie, communicating with the periphery of said bed, for delivering products of decomposition to said combustion chamber and to the orifices in said baffle.

2. Apparatus for decomposing a catalytically decomposable liquid into gaseous products of decomposition, comprising;

a chamber having opposed spaced imperforate walls and a central opening extending therebetween, defining an annular space,

a bed of at least two juxtaposd porous strips of substrate screen material having catalytic surfaces wrapped in a spiral around said central opening, one screen being straight out and the other bias cut, and

means for delivering a catalytically decomposable liquid to said central opening for outward flow therefrom in all radial directions through the bed, the products of decomposition exhausting throughout the periphery of the bed.

3. Apparatus in accordance with claim 2 including a fuel conduit extending axially through said central opening and in heat transfer relation to surrounding decomposable liquid delivered to said central opena fuel injection nozzle disposed adjacent one side of said bed and communicating with said conduit, and

means for delivering fuel to said conduit,

the construction and arrangement being such that heat conducted to the fuel delivered through the conduit is transferred to said surrounding decomposable liquid.

4. Apparatus in accordance with claim 3 wherein said nozzle comprises a plurality of angularly spaced injection orifices arranged to inject the fuel in outwardly directed streams from the surf-ace of a cone,

an annular baflle surrounding said nozzle having a plurality of angularly spaced orifices arranged to deliver gaseous products of decomposition in inwardly directed streams along the surface of a cone and intersecting the streams of fuel, for atomizing same,

a combustion chamber disposed adjacent said nozzle,

and

an annular passage surrounding said bafiie, communicating with the periphery of said bed, for delivering products of decomposition to said combustion chamber and to the orifices in said bafile.

References Cited UNITED STATES PATENTS 2,607,663 8/1952 Perry 252,477 2,887,456 5/1959 Halford 252477 3,040,521 6/1962 Broughton -257 3,091,520 5/1963 Newburn 60257 3,135,089 6/1964 Davis 60-257 3,171,251 3/1965 Pauli 60-258 3,230,707 1/1966 Rothmayer 6039.46

CARLTON -R. CROYLE, Primary Examiner.

DOUGLAS HART, Assistant Examiner.

US. Cl. X.R. 431183 

